title: Dehydrin-like proteins in the necrotrophic fungus Alternaria brassicicola have a role in plant pathogenesis and stress response.
abstract: In this study, the roles of fungal dehydrin-like proteins in pathogenicity and protection against environmental stresses were investigated in the necrotrophic seed-borne fungus Alternaria brassicicola. Three proteins (called AbDhn1, AbDhn2 and AbDhn3), harbouring the asparagine-proline-arginine (DPR) signature pattern and sharing the characteristic features of fungal dehydrin-like proteins, were identified in the A. brassicicola genome. The expression of these genes was induced in response to various stresses and found to be regulated by the AbHog1 mitogen-activated protein kinase (MAPK) pathway. A knock-out approach showed that dehydrin-like proteins have an impact mainly on oxidative stress tolerance and on conidial survival upon exposure to high and freezing temperatures. The subcellular localization revealed that AbDhn1 and AbDhn2 were associated with peroxisomes, which is consistent with a possible perturbation of protective mechanisms to counteract oxidative stress and maintain the redox balance in AbDhn mutants. Finally, we show that the double deletion mutant ΔΔabdhn1-abdhn2 was highly compromised in its pathogenicity. By comparison to the wild-type, this mutant exhibited lower aggressiveness on B. oleracea leaves and a reduced capacity to be transmitted to Arabidopsis seeds via siliques. The double mutant was also affected with respect to conidiation, another crucial step in the epidemiology of the disease.
authors.affiliation: Université d'Angers, UMR 1345 IRHS, SFR QUASAV, Angers, France ; INRA, UMR 1345 IRHS, Angers, France ; Agrocampus-Ouest, UMR 1345 IRHS, Angers, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Pochon
authors.forename: Philippe
authors.initials: P
authors.lastname: Simoneau
authors.forename: Sandrine
authors.initials: S
authors.lastname: Pigné
authors.forename: Samuel
authors.initials: S
authors.lastname: Balidas
authors.forename: Nelly
authors.initials: N
authors.lastname: Bataillé-Simoneau
authors.forename: Claire
authors.initials: C
authors.lastname: Campion
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Jaspard
authors.forename: Benoît
authors.initials: B
authors.lastname: Calmes
authors.forename: Bruno
authors.initials: B
authors.lastname: Hamon
authors.forename: Romain
authors.initials: R
authors.lastname: Berruyer
authors.forename: Marjorie
authors.initials: M
authors.lastname: Juchaux
authors.forename: Thomas
authors.initials: T
authors.lastname: Guillemette
mesh_terms: D000528:Alternaria / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D005615:Freezing; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D016681:Genome, Fungal / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D018384:Oxidative Stress / Q000187:drug effects; D020675:Peroxisomes / Q000187:drug effects / Q000378:metabolism; D010944:Plants / Q000382:microbiology*; D012333:RNA, Messenger / Q000235:genetics; D012492:Salts / Q000494:pharmacology; D012639:Seeds / Q000382:microbiology; D013312:Stress, Physiological / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D005656:Fungal Proteins; D012333:RNA, Messenger; D012492:Salts